In existing underground mining machines, such as load-haul-dump machines, the heating, ventilation and air conditioning (“HVAC”) components are positioned in various locations around the machine. This can make maintenance of a HVAC system difficult and time consuming.
Exterior of the cab, a compressor charges a refrigerant fluid to the optimum pressure for cooling efficiency and circulates it around the system. A condenser and fan package is located near the engine radiators. The condenser and fan cools the refrigerant at high pressure, so that at discharge the refrigerant potential thermal energy is well below that of the ambient environment.
Within the cab of the machine, an evaporator core and blower unit are co-located in a conditioner box, typically attached to the ceiling of the cab. The evaporator core cools air that is pushed through by the blower. Assisting the evaporator core is an expansion valve, which regulates the refrigerant flow within the evaporator. Allowing expansion of the fluid within the evaporator increases the potential cooling capacity, as the expansion further cools the fluid.
An optional heater core utilises warm engine coolant to heat the same air stream, if the operator is cold. A pressuriser is mounted on the cab outer wall and provides fresh air at a higher-than-ambient pressure to the cab. This ensures that any air leaks result in an outward flow from the cab to the environment.
The mounting of various components within the cab encroaches on the limited space available for the operator. Having the conditioner box located near the head of the operator can result in possible head injuries and also elevated noise levels. It also makes direction of the air difficult to control, particularly for demisting requirements.
The spacing out of various components can result in efficiency losses and poor control of the airflow, decreasing performance. It also makes servicing difficult, as mountings and couplings must be in easy-to-reach locations, and can prove time consuming to troubleshoot.
Whilst there have been a number of HVAC system designs that co-locate more of the components together, these are typically designed for above ground machines. However, underground machines have a further limitation on space due to the restricted width and ceiling height of underground tunnels. As the tunnels do not allow for turning of a vehicle, underground load-haul-dump machines run both backwards and forwards along the tunnel. Load-haul-dump machines are long and narrow and have a relatively low cab, with a driver typically sitting transverse to the direction of travel. The machine is articulated in its centre to provide steering capacity. All of these factors result in poor operator visibility. Therefore, the location of external components on a machine is critical to ensuring sufficient visibility is provided for the operator.
The present disclosure is directed to one or more of the problems identified above.